--- nsis-2.46-src.old/Source/util.h	2009-03-28 09:47:26.000000000 +0000
+++ nsis-2.46-src/Source/util.h	2012-01-16 12:22:14.967416817 +0000
@@ -17,6 +17,8 @@
 #ifndef _UTIL_H_
 #define _UTIL_H_
 
+#include <unistd.h>
+
 #include <string> // for std::string
 
 #include "boost/scoped_ptr.hpp" // for boost::scoped_ptr
